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3 years ago

Calculate the concentrations of all species present in a 0.26 M solution of ethylammonium chloride (C2H5NH3Cl).

Chemistry

1 answer:

Alina [70]3 years ago

5 0

Answer:

0.00000223

Explanation:

pKa for C2H5NH3+ = 10.7

pKw = 14.0

pKa + pKb = pKw

10.7 + pKb = 14.0

pKb = 14.0 - 10.7

pKb = 3.30

C2H5NH3Cl is a salt of ethylamine and HCl so it will dissolve in water to produce C2H5NH3^+ + Cl^-

The base hydrolysis reaction: C2H5NH3^+(aq) + H2O(l) <=> C2H5NH2(aq) + H3O^+(aq)

This reaction is described by Kb.

Kb = [C2H5NH2][H3O^+]/[C2H5NH3^+]

Let [C2H5NH2] = [H3O^+] = x,

so [C2H5NH3^+] = 0.26 - x

Kb = x^2/(0.26 - x) = 2.00 x 10^-11

Let's solve for x. In this equation, It is possible to solve without the use quadratic equation. So we can assume that 0.26 - x is approximately equal to 0.26. We won't know until we do the calculation.

We get: x^2 + 2.00 x 10^-11x - 4.99 x 10^-12 = 0

With the use of a quadratic calculator.

x = 2.23 x 10^-6 M = [C2H5NH2] = [H3O^+]

0.26 - x is just 0.26 M in this problem because 2.23 x 10^-6 M is insignificant.

[C2H5NH3^+] = 0.26 M = [Cl^-]

NOTE:

pH = -log [H3O^+] = -log(2.23 x 10^-6) = 5.65

Ka is the acid dissociation constant

Kb is the base dissociation constant

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Calculate the Ph and the POH of an aqueous solution that is 0. 040 m in HCl(aq) and 0. 075 m in HBr(aq) at 25 °C.

LenaWriter [7]

pH is the measure of the hydrogen ion concentration while pOH is of hydroxide ion concentration in the solution. The pH is 0.939 and pOH is 13.061 pOH.

pH is the concentration of the hydrogen ion released or gained by the species in the solution that depicts the acidity and basicity of the solution.

pOH is the concentration of the hydroxide ion in the solution and is dependent on the pH as an increase in pH decreases the pOH and vice versa.

Both HCl and HBr are strong acids and gets ionized 100 % in the solution. If we let 1 L of solution for the acids then the concentration of the hydrogen ion will be 0.100 M.

Since both completely dissociate we would just add the molarities of each of the H+ ions together and then calculate the PH and POH from that :

HCL(0.040M)----> H+(0.040M) +CL-(0.040M)

HBr(0.075M)----> H+(0.075M) +Br-(0.075M)

so 0.040M (H+ from HCL) + 0.075M (H+ from HBr) = 0.115M H+ in total.

pH is calculated as:

pH = -log[H+]

Substituting values in the equation:

log(0.115M)= 0.939 pH

pOH is calculated as:

14 - pH = pOH

Substituting values in the equation above:

14 - 0.939= 13.061 pOH

Therefore, pH is 0.939 and pOH is 13.061.

Learn more about pH and pOH here:

brainly.com/question/2947041

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5 0

1 year ago

55 L of a gas at 25oC has its temperature increased to 35oC. What is its new volume?

ladessa [460]

Answer:

Approximately 56.8 liters.

Assumption: this gas is an ideal gas, and this change in temperature is an isobaric process.

Explanation:

Assume that the gas here acts like an ideal gas. Assume that this process is isobaric (in other words, pressure on the gas stays the same.) By Charles's Law, the volume of an ideal gas is proportional to its absolute temperature when its pressure is constant. In other words

$\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1}$ ,

where

$V_2$ is the final volume,
$V_1$ is the initial volume,
$T_2$ is the final temperature in degrees Kelvins.
$T_1$ is the initial temperature in degrees Kelvins.

Convert the temperatures to degrees Kelvins:

$T_1 = \rm 25^{\circ}C = (25 + 273.15)\; K = 298.15\; K$ .

$T_2 = \rm 35^{\circ}C = (35 + 273.15)\; K = 308.15\; K$ .

Apply Charles's Law to find the new volume of this gas:

$\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1} = \rm 55\;L \times \frac{308.15\; K}{298.15\; K} = 56.8\; L$ .

8 0

3 years ago

I In a smaller room, such as a bathroom, the reflected sound can reverberate (echo in many directions) off the smooth tile. Why

AVprozaik [17]

Answer:

See explanation

Explanation:

It is common knowledge that quite a number of people enjoy singing in the shower. There are reasons for this!

In the shower, there are many surfaces that reflect the sound of your voice as you sing. That makes your voice to sound more powerful and have more volume.

The reverberation of the sound makes the sound of your voice stronger and more intense altogether enriching the music produced as you sing.

5 0

3 years ago

Calculate the eccentricity of an ellipse. The distance between the foci is 5.2 and the length of the major axis is 20.6.Round of

Dominik [7]

Answer:

The eccentricity of the ellipse is 0.252.

Explanation:

The eccentricity of an ellipse ( $c$ ), dimensionless, can be determined by means of the following expression:

$e = \frac{\bar c}{\bar a}$ (1)

Where:

$\bar c$ - Distance between the foci, dimensionless.

$\bar a$ - Length of the major axis, dimensionless.

If we know that $\bar c = 5.2$ and $\bar a = 20.6$ , then the eccentricity of the ellipse is:

$e = \frac{5.2}{20.6}$

$e = 0.252$

The eccentricity of the ellipse is 0.252.

8 0

3 years ago

Which Of These Is An Indication That A Chemical Reaction Has Occurred?

nikdorinn [45]

Answer:

Correct option is D. Formation Of A Gas

Explanation

The main indication of chemical is that new substances are formed which have different composition than reactant.

Freezing of a substance: As in this case composition remained same, so we cant say, chemical reaction is take place, like when water freezes, it composition is same as water , so it is only its physical properties, not chemical.

Melting of a substance: As in this case composition remained same, so we cant say, chemical reaction is take place, like when ice melts, composition of water remained same , so it its physical properties, not chemical.

Boiling of a substance: As in this case composition remained same, so we cant say, chemical reaction is take place, like when water boils and become vapors, composition of water and vapors remained same , so it its physical properties, not chemical properties which show its chemical reaction.

Formation of gas:

In this case, chemical reaction take place. In chemical reactions, new substance are formed whose composition is different from reactants.

6 0

3 years ago

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